1. Field of the Invention
The present invention relates to a control device designed to control a vehicular drive device that has a rotating electrical machine provided in a drive train path connecting an input member drivingly coupled to an internal combustion engine with an output member drivingly coupled to wheels, has a first engagement device provided between the input member and the rotating electrical machine, and has a second engagement device provided between the rotating electrical machine and the output member.
2. Description of the Related Art
As a control device as described above, there is already known a device described in Japanese Patent Application Publication No. 2008-7094 mentioned below. This control device is designed to control a drive device for a hybrid vehicle of a so-called one motor parallel type. This control device causes the vehicle to run while transmitting to an output member (a propeller shaft) a torque of an internal combustion engine (an engine) transmitted to an input member when both a first engagement device (a first clutch in Japanese Patent Application Publication No. 2008-7094; the same will hold true hereinafter) and a second engagement device (a second clutch) are in a slip engagement state in a CL2 overheat mode (a kind of WSC running mode) in Japanese Patent Application Publication No. 2008-7094. It should be noted that in this control device, the second engagement device is subjected to torque control so as to transmit a required torque needed to cause the vehicle to run, and a rotating electrical machine is subjected to rotational speed control on the basis of a predetermined target rotational speed.
In the control device of Japanese Patent Application Publication No. 2008-7094, the control for causing the rotating electrical machine (a motor-generator) to carry out electric power generation using part of the torque of the internal combustion engine may be performed, for example, when a storage amount of a storage device is small. In this case, the internal combustion engine is so controlled as to output a torque equivalent to a sum of the required torque and a torque needed for electric power generation by the rotating electrical machine. At this time, an electric power generation amount achieved by the rotating electrical machine is determined on the basis of a differential torque as a difference between an output torque of the internal combustion engine transmitted to the rotating electrical machine side via the first engagement device and a torque transmitted to wheel side via the second engagement device and a target rotational speed of the rotating electrical machine subjected to rotational speed control.
However, in real control, the output torque of the internal combustion engine and a transfer torque capacity of the second engagement device do not always completely coincide with their control target values, and inevitably vary to a certain extent. Then, when such variations occur, the aforementioned differential torque fluctuates greatly, so that the electric power generation amount achieved by the rotating electrical machine may also fluctuate greatly.